Plastic liners characterized by a facing surface of a low coefficient of friction and suitable for use as bearing liners have been prepared by a number of techniques. Typically, such liners are employed by securing the laminate lining to a reinforcing or supporting surface, such as a roughened surface of a bearing, wherein the liner serves as a bearing liner. The liner is bonded to the supporting surface employing a thermosetting resin material. The facing surface of the liner typically contains a plastic having low-friction properties which impart a low-friction facing surface to the bearing liner. Such facing surfaces are typically composed in part of a low-friction polymeric thermoplastic material, such as a fluorocarbon resin like tetrafluoroethylene (TFE). Such polymeric materials permit low-friction sliding, rotational or other contacting engagement or movement between two parts. For example, such liners with such resins have been found particularly useful between the ball and the race of a ball joint, in plane journal bearings wherein the liner is secured to the inside diameter of the cylindrical journal, in rod end bearings and in other devices where low friction between sliding, rotating or contacting parts is desired.
In the past, bearing liners have been prepared wherein the liner is composed of a combination of low-friction polymeric strands and resin-bondable strands interwoven together; for example, the use of tetrafluoroethylene resin strands and cotton or glass fibers which have been interwoven together and used in bearing liners. The bearing facing surface is normally composed primarily of the low-friction polymeric strands, while the opposite or backing surface is normally composed primarily of the resin-bondable strands. A thermosetting-type resin is then employed to impregnate the bondable strands, and the resulting liner is then resin-bonded under heat and pressure to the desired bearing surface. In this type of bearing liner, the facing surface derives its low-friction properties from the presence of the interwoven polymeric strands (see U.S. Pat. Nos. 2,885,246; 2,907,612; and U.S. Pat. No. Re. 24,765).
Other bearing liners have been prepared employing a facing surface composed of low-friction suspended or powdered polymeric particles dispersed in a resin binder with or without the presence of low-friction strands, wherein various molding compositions employed have bearings (see U.S. Pat. Nos. 3,471,207; 3,533,668; and 3,594,049). In addition, several techniques have been used to prepare various bearing liners, including the use of adsorbent sheet materials adjacent a low-friction facing surface of polymeric strands to avoid excess resin adhesive being forced onto the facing surface during their manufacture (see U.S. Pat. No. 3,055,788), while other techniques use a lamination manufacturing method which includes a graphite tissue impregnated with tetrafluoroethylene resin sheet material (see U.S. Pat. No. 3,501,360). Prior art liners and their use as bearing liners and their manufacture have not been wholly satisfactory, and, as evidenced by the continuous modifications made to such liners and bearings in the field, improved liners and bearings which require less initial wear-in time and better wearing life, which are thinner or possess other desirable characteristics are constantly being sought.